Newton's theory of optics. Halley identified his comet and is appointed Astronomer Royal at Greenwich. Bradley discovers aberration of light and is appointed Astronomer Royal at Greenwich. Newton's Principia translated into English. Transit Room built at Greenwich Royal Observatory, home of Bradley's Greenwich Meridian. Franklin shows that lightning is electricity. Britain adopts Gregorian calendar, eleven days lost. Industrial Revolution begins with Arkwright spinning machine. Herschel discovers Uranus. Laplace publishes Laws of the Planetary System. Hutton starts scientific geology.